I have 5 black skirt tetras in a 27 gallon planted tank. The P.H. IS 6.5 AND water temperature is 72 degrees fairenheit. I noticed today that one of the black skirts was a lot bigger then all the others. It has also been following only one other black skirt which has longer fins then the rest. Please help me, I need to know so I can set up a seperate aquarium. Thanks_________________INEEDMORETANKS!!!!!